OTA Antenna Array Subsets for Compact Far-Field Measurement
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Solution Overview
Problem
Existing measurement systems for electronic devices with integrated RF antennas require large test chambers due to the need for far-field conditions, which is inefficient and undesirable.
Innovation Solution
A measurement method using a phased array antenna system that can switch between near-field and far-field modes, allowing for reduced spatial requirements by using a subset of antennas to perform measurements on devices with varying sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If far-field measurement conditions are used, then measurement accuracy is improved, but test chamber size increases
Solution Approach 1:
The measurement antenna array is divided into multiple antenna elements arranged in concentric rings, allowing selective activation of subsets of antennas. This segmentation enables the system to perform far-field measurements with a smaller effective aperture by using only the necessary number of antenna elements, thereby reducing the required test chamber volume while maintaining measurement accuracy.
Solution Approach 2:
The system dynamically adjusts which antenna elements are active in the measurement array based on the specific measurement requirements and device under test characteristics. By dynamically configuring the antenna subset, the system can achieve accurate far-field measurements with variable spatial requirements, optimizing the balance between measurement precision and chamber size.
2Measurement precision
If measurement antenna array size is increased, then measurement accuracy for large antennas is improved, but spatial requirements increase
Solution Approach 1:
The measurement antenna array is designed to serve multiple functions: it can perform measurements for devices of various sizes by dynamically selecting appropriate antenna subsets. The same physical array structure can be configured to provide different effective apertures, making the system universally applicable to both small and large antennas without requiring multiple dedicated arrays or increasing the maximum spatial requirements.
Solution Approach 2:
Different subsets of antenna elements are activated based on the specific measurement needs and device characteristics. Rather than requiring the entire array to be active for all measurements, the system activates only the locally necessary antenna elements, optimizing the use of spatial resources while maintaining measurement accuracy for each specific case.
3Volume of stationary object
If a subset of measurement antennas is used, then spatial requirements are reduced, but measurement capability must be maintained
Solution Approach 1:
The system changes the operational parameters by selectively activating different antenna elements and adjusting their weighting factors. This parameter adjustment allows the same physical antenna subset to achieve different measurement capabilities, ensuring that reduced spatial requirements do not compromise measurement precision. The weighting factors are optimized to maintain measurement accuracy with fewer active elements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces the size of the measurement system, enabling efficient testing of devices with both accessible and non-accessible RF ports, and supports both continuous and digitally modulated signals.
Implementation Method 1
receiving, by means of the selected measurement antenna subset, electromagnetic waves generated by the at least one antenna to be tested
Data Source
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AI summary
A measurement method of performing over-the-air (OTA) measurements on a device under test (12) is described. The measurement method comprises the steps of - providing a measurement antenna array (14), wherein the measurement antenna array (14) comprises a plurality of measurement antennas (40) having an adjustable signal weight to a measurement signal processed by the measurement antenna array (14), respectively; - selecting, by means of a control circuit (22), a measurement antenna subset (38), wherein the measurement antenna subset (38) comprises at least one of the plurality of measurement antennas (40); - receiving, by means of the selected measurement antenna subset (38), electromagnetic waves generated by at least one antenna (34, 36) to be tested, thereby obtaining the measurement signal that is forwarded to a processing circuit (24); - receiving, by means of the processing circuit (24), a reference signal from a reference signal source; and - determining, by means of the processing circuit (24), at least one measurement parameter associated with the at least one antenna (34, 36) to be tested based on the measurement signal and based on the reference signal. Further, a measurement system (10) for performing OTA measurements on a device under test (12) is described.